Impact-engine.



Patented Apr. 22, |902.

No. 693,2-7l. I

N. GILPATRICK.

IMPACT ENGINE.l

(Application filed Feb. 13, 1901.)

(Nu Model'.)

. .wilmll UNITED STATES PATENT` OFFICE.

`- n-EHEMIAH GILPATRICK, on s T. JOHNSBURY, VERMONT.

IMPACT-ENGINE.

srnciricnrrorr fgnning part of, Letters raient No. 698,271, daeeanprn 22, 1902. i

` Application-Hired February 13, 1901.` Serial No. 47,182. (No model.)

To all whom r34 mau/jammern:

Beit known that LNEHEMIAH'GILPATRICK,

have invented'certain Improvements in Impact-Engines, of which the following is a specication.

My invention relates to that class of percussive engines known*y as pneumatic impacttools ;and it consists of certain improvements in machines of this character and'in the valve for operating the same, whereby I am enabled to increase the efficiency of the tool and effect a stroke of any desired length with a piston or plunger of any desired size.

My invention is fully illustrated in the accompanying drawings, in ,which- Figure 1 is a longitudinal view of the tool, mainly in section. Fig.2 is a longitudinal sectional plan View taken on the lines ct a, Fig. 1. Fig. 3 is a cross-sectional view of the cylinder,l valve, and valve-block, taken on the lineb b, Fig. 1; and Figs. 4, 5, and 6 are sectional views illustrating modifications of the valve and valve-block. i Although the several improvements forming the subject of my invention are appli- 4cable to pneumatic tools in general, I have shown them in'connection with along cylin der, -making what is known as a long' stroke tool, the chamber of such tool being approximately three times the length of the piston. Y j

In my improved tool the Valve isso ar'- -ranged with respect to the cylinder that'the chamber of the latter is unobstructed by4 said valve or the valve-block, and hence a stroke of greater length ,may be obtained than has hitherto been possible with this class of tools.

This valve is located outside the cylinder and is arranged to move in a line parallel `to a line drawn through the center of vthe cylinder at right angles to the same. -The valve is contained within avalve-block having suit-f able ports land passagesfor the iiow ofthe motive liuid, whereby vsaid valve may be shifted automatically during the movement ot the piston or plunger.

In the drawings herewith, 1 represents the outer shell or casing of the tool, and2 is the inner sleeve, within which is formed the chamber for the passage of the piston or plunger 4. The outer shell 1 is preferably shrunk onto the inner sleeve 2, so that whenl completed the cylinder is practically one piece.

5 is the handpiece or handle, having a socket l 6 to receive said cylinder, an opening V7 for the reception of the valve-block 8, and hav- 'ing also an opening 9, in which may be seand the stock of the tool may be iitted directly into the same, a gasket 17 of suitable material packing said stockand serving to prevent leakage at this point. Touassist in retaining' the cap 15 in place,I arrange a section of wire spring 1S between the end of said cap and the bottom of the recess 16, and as Van extra precaution to prevent the turning of said cap 15 a finely threaded setscrew 19 is arrangedin'a suitable hole tapped into the cap and handpiece. l

` The inlet of motive iiuid to the tool is con trolled by a throttle-valve 20, consisting of a hollow tube-like section or sleeve which closes the opening9, in which the tube leading from .v the pressure apparatus is secured. For the purpose of conveying the motive fluid to the chamber of the valve-block from said opening 9 I provide the screwplug 21, carrying a tube-like projection 22, which has a port 23, closed by the valve 20. This valve surrounds the tube projection 22 and is movable 0n the same, being operated by a lever 211, pivoted at 25 to the handpiece, the latter being slotted for this purpose and a spring 26 beingprovided, whereby said valve is normally held in the closed position. The lever 24 is provided with a pin 27, which passes througha slot 28, v

formed ina lug 29, secured to the side of the throttle-valve. It is necessary to slot the handpiece at 30 to provide for the passage of the connection of the valve 20 with the lever 24, and in order that this slot may be vot' suficient length to permit the proper movement of the valve and yet be closed during extreme ICO movement of the same I extend saidvalve at one side, as at '31, and recess the screwplug at 32 to receive said extension.

Locatedin the opening '7,formed in the handpiece, and arranged outside the piston-chamber on a line parallel to a line drawn through the center of the cylinder at right angles to the same is the valve-block 8, in the present instance made in two pieces which are held in place in the opening in the handpiece by the pins 33, let into the end wall of the latter. Each half of the valve-block is provided with recesses 34, adapted to receive doWel-pins 35, so that the ports, passages, and recesses in said block will register when the halves are put together. To hold the valve-block in the recess 7, I provide the screw-cap 3G, which is provided with depressions 37 to receive the prongs of a suitable key for turning it into place.

The valve-block has a series of ports, passages, and recesses, shortly to be described, and has a piston-valve centrally located therein, said valve having heads 38 at each end, preferably ofthe same diameter, though I do not wish to limit myself to this precise construction, said heads 33 being adapted to the end bores of the valve-block. The valve is also provided with a central disk 39, preferably of less diameter than the heads 33, and this disk 39 is adapted to the central bore of the valve-block. The heads 33 and disk 39 of the valve are connected together by a stem 40 of reduced diameter, and said valve is arranged in the valve-block before the halves of the latter are put together.

Instead of making the valve-block in two halves, as shown in Figs. 1, 2, 3, and 5, I may make the main portion or barrel 8L in one piece, as shown in Fig. 4, with a central bore extending through the same, such bore to be the same as that of the valve-block shown in Figs. l, 2, and 3-that is to say, with the end bores of greater diameter than the middle bore. With this form of valve-block it will be necessary to make the valve in two pieces, as shown in Fig. et, in which one of the heads 3Sfis detachable, being adapted to the threaded end of the stem 40% The through-bore of the valve-block is closed by means of screwplugs 4l, which serve as the end walls of the valve-chamber and determine the length of stroke of the valve.

In the valve-block 8 is a recess 4.5, communicating with the inlet-passage in the tube projection 22, controlled bythe throttle-valve 20, such communication being through the passage 46, and 4:7 is a passage leading from the valve-block to the piston-chamber, 4communication between this passage and the rccess 45 being around the stem 40 of the piston-valve, as shown in the drawings.

The passage -l-' is extended from the valveblock through the cylinder and terminates in the form of a shallow groove 48, cut into the inner wall of the piston-chamber below the port-opening, such shallow groove providing for thc transit of the motive fluid to the piston gradually to prevent shock and assisting in the rapid removal of such force from in front of the piston on the return stroke of the same. An exhaust-recess 49 is located in the valve-block, and such recess communicates with the atmosphere through openings 50, extending through said block and the handpiece-casing. Alongside the recess 49 is a similar recess 5l, connected with the main exhaust-passage 52, the latter communicating with the piston-chamber through the port 53 near the end of the same opposite the valve. Communication between the recesses 49 and 5l is afforded around the stem 40 of the piston-valve. The main exhaust-passage 52 is formed between the casing 1 and the inner sleeve 2 by grooving the outer surface of the latter. A recess 5-1 is also located inthe valveblock for exhausting the motive [luid from in front of the piston on the return stroke of the same. This recess communicates with the atmosphere through the passages 55, cut through the valve-block and shell of the handpiece, as clearly shown in Figs. l and 3.

Located within the valve-block and communicating with the ends of the valve-chamber is a passage 60, said passage forming a duct to convey motive fluid to move the valve within the valve-block, such fluid holding the valve in the changed position whatever such position may be. This passage (if) communicates with the recess 45 in the valveblock by means of the port (5l and with the valve-chamber by means of the short end passages 62 and G3. This passage G0 also communicates with the passages Gil and G5,which open into the piston-chamber,through the ports 6G and G7, the former near the port 53 and the latter at a point near the valve-block.

The passages 64E and 65 are of less area than the passage 52, but, like the latter', are formed by grooving the outer surface of the inner sleeve 2. They are provided to permit the motive Iiuid to leak or weep into the pistonchamber, so that the valve will be held in the different positions during the movements of the piston by the initial pressure of the motive Huid acting upon the inner surface of the enlarged ends 3S of the valve.

The motive fluid entering the recess Ll5 in the valve-block besides serving to move the piston in the chamber 3 passes into the passage GO and thence to the valve chamber through the end passage G3 and acting upon the enlarged end of the valve will hold the same in the position shown in Figs. 2, 3, and el of the drawings. At the opposite end of the valve-block, however, the motive fluid cannot enter the passage 62, and the excess of such pressure leaks into the chamber 3 through the passage G4: and port 6G in advance of the piston and passes from said `chamber through the port 53, passage 52,

thence to the recesses 5l and 49 in the valveblock, and from the latter to the atmosphere through the openings 50. Although this leakl age through the passage Gi is constant during thejforwardmovement of the piston and throughfthe passage 65 on the returnstroke of said piston, the volume of `motive fluid so lost is so little as to have no appreciable effeet upon the operation of the tool. Asthis leakageinto the'passage 64 is taking place adjacent to the passage 62,leading t one end of the valve, said valve will not be moved, particularly as pressure is vpassing from the passage 60 'throughV the end passage 63 to the opposite end of the'valve-chamber and tending to hold the valve in theposition shown' in Figs. 2, 3, and. 4 of the drawings.

This same result might be attained'by having a Valve with a central disk of greater diameter than'the heads and changing the former eX- haust-recesses to inlet-recesses andthe form er inlet-recess to an exhaust-recess. Such construction I have illustrated'in Figs. 5* and 6. In Fig. the valve is shown in a position opposite to that shown in Figs. 2, 3, and 4. In this Valve the heads 38b are provided land the central disk 39", of a greater diameter than said heads, said .disk andrheads `being connected by the stem 40". In this structure the motive fluid enters from the passage 46 and passes into a two-Way duct 56. one end'of this duet 56 the motive fluid enters *the recess 543 and passing around the stem 40b of the valve'enters thepassage '47o and from there passes intothepiston-chamber be-y hind the piston. The exhausting fluid from in front of .the piston-is meanwhile passing `its `initial position.

Ithrough the exhaust-passage 52, which' communicates withl the recess 51b in the valveblock, and from said recess it passes around thestem 40b vof the-valve to'therecess 45b and from-the latter to the atmosphere through the openings 57. When the valve is shifted as the piston reaches jthe end of its stroke,gt`ne motive fluid will pass from. the opposite end of the two-way duct 56 to the recess 49b,thenc`e around the stem 40b of the' valve to the recess 511?, and from the latter to the passage 52 of the cylinder, entering the piston-chamber from` the portl 53 at the rear of the moving piston and serving to return said piston to As the piston is'retracted the fluid in front of the same passes from the piston-chamber-throughthe passage 47,v

thence around the Valve-'stem-40b to the recess 45", and from this latterrecess to the at'- mospherethrough the vopenings 57.v vIn this form of structure the passage b communicates w-ith the recesses 49b and 54b'through p The effectof thispassage 60b and the Vend passages 62h. and-63b, `which latter communicatewithA the passages 64 and 6 5 i. 6ov

of the cylinder, is the same Vas Withv the other 1 structures.

v .The operation ofthe toolisas folloivszL Mo?. tive` :fluid beingV admitted tto the' passage 46 in the handpiece through ythethrottle-valve 2 0.'

and'tubular stem-22,1any airlwithinthe .tool will pass `out through the port 53 and passage 52 of .the cylinderfto the' exhaust-recess49, and thence through the openings 50 inthe From ving into the piston-chamber through thepor Vvalvecould be maintained in the-*proper tion maybe continued indefinite valve-block and handpiece to the atmosphere. The incoming motive .ffluid passes from the 1 passage 46 to the recess 45 in thevalve-block, thence around the stem 40 of the piston-valve Atthe same time a portion ofthe .motive i'luid is leaking or Weeping into the piston-` chamber ahead of the piston from the passage j 64 through the port 66, such leaking fluid being removed from said chamber through the` port 53 and passage 52 with the other exhaust-1 i, i ing iluid.` When'the piston reaches theend p l y ofits stroke, the port 66 is closed'andthe 1 to the passage 47 in said block, and 'from this f latter passage enters the piston-chamber be'` .o hind the piston-and moves the latter forward.

motive fluid which iillsthe passage 60 in the valve-block is thereby trapped at the end pas'- Y sage 62 and passes to theendV of the valvechamber instead of passing into the piston# Chamber-1 The pressure against bothendsf.

the valve is now'equ'al through the motive' iluid filling both passages 62 and 63; butthe full pressure of the motive fluid being ld-i.

rected against the innersurface of one ofthe heads of the valve the latter will be moved to g a position opposite to that shown in Figs. 2,

3, and 4 of fthe drawings. This' actionwill g.-

be accomplished, as the surface of thejValve-j' head exposedto the full pressureof' themetive fluid is greaterthanl `the surface of the' central disk 39 of the Valve. Whenthe' valve;

is in either position, 'it maybe shifted-Joythe-- Io i the surface of the-central disk when theend 4.

full pressure of the motive lluid actingupon pressures are equal. The Valvehaving now@ been shifted to a position opposite to thatf shown invFigs. 2, 3, and 4 `o f the drawings,

the motive'lluid from the inlet-passage 46 will;

pass to the recess 45, from whi'chit 'passes u around the valve-stem 40 to the recessl, `and thence tothe passage 52, extending through the cylinderofthe tool. 52 the motive fluid enters the piston-cham-t From this passage.vv

ber through the port 53, and getting behindy the'piston the latter will befreturned'toits p original position.y During this movement-of'` the piston the fluid infront of the same'has been exhausting to the atmosphere through the openings 55cut through the valve-block andcasing from the recess v54, suchexhaustving fluid p'assingto vthe same from. thepas sage 47of the valve-block around'th'estem- 40 ofthe valve. Until the moving pistonh'as cut it 'off' the motive fluidhas also loee'anflea'k-l 67 from the passage '65, so that the pisto sito, Such passage@ `the passage 60 in tlg-@yal e? l tervwith lthe 'end'passagef62,leadin outer` surface ofthe head;A 'offA the val passages 64 and 65,'communicating j end passagesV 62; and ,l respectively,y`

nately;bleedthe'fullfpressureandconveythl same to the heads'ofkfth'e yalve. j-T sopera p Themodiflcationsfsh Wn in th 4, 5, and G extend only to the valve and valveblock, the structure of the rest of the tool remaining the same.

Having thus described my invention, I claim and desire to secure by Letters Patentl. In a pneumatic hammer, a cylinder, an im pact-piston therein, a sleeve detachably secured to one end of the cylinder, said sleeve having a recess formed in one side of the same at right angles to the cylinder and out of line of the same, a chambered valve-block arranged in said recess and communicating directly with the cylinder, and a fluid-actuated piston-valve arranged Within said block, substantially as described.

2. In a pneumatic hammer, a cylinder, an impact-piston, a handle portion having a sleeve by which it is detachably secured to the cylinder, said sleeve having a recess formed in one side ofthe same at right angles to and out of line of the cylinder, a chambered valve-block arranged in said recess havinga differentially-Mead valve-chamber formed therein, and a Huid-actuated and differentially-aread piston -yalve arranged in said valve-chamber, substantially as described.

3. In a percussive engine, the combination of a cylinder, a piston movable within said cylinder, a valve controlling the inlet and outlet of the motive uid to and from the cylinder, said cylinder being provided with a longitudinal opening leading from the valve for theinitial passage of the motive fluid, substantially as and for the purpose set forth.

a. Inapneumatichammer,thecombination of a cylinder, a pistou movable Within said cylinder, a valve-block located wholly outside of the cylinder, a diierentiallyaread piston-valve located Within said valve-block, said valve adapted to move in a line at right angles to and out of line of the cylinder, said cylinder having passages of reduced area communicating with passages of the 'same area Within the valve-block, whereby the motive fiuid may be conveyed to the ends of the piston-valve to hold the same in the different positions, said valve being moved by the initial pressure of the motive fluid.

5. In a pneumatic hammer,thc combination of a cylinder, a piston movable Within said cylinder, a valve-block located wholly outside of the cylinder, a valve arranged within said valve-block and adapted to move at right angles to and out of line of the cylinder, said cylinder having a series of passages of reduced area, and said valve-block having similar passages communicating therewith, the passages of the cylinder opening into the op posite ends of the same, substantially as and for the purpose set forth.

G. In a pneumatic hammer, a cylinder, an impact-piston, a handle portion having a sleeve by Which it is detachably secured to the cylinder-,and cushioning means interposed between said cylinder and the handle portion.

In testimony whereof I have signed my name to this specification in the presence ot' two subscribing Witnesses.

NEHEMIAH GILPATRICK.

\Vi tn esses:

ERNEST GILPATRICK, GUY W. HILL. 

